The Confederation for British Industry (CBI) and the Trade Union Congress (TUC) — which represent 190,000 businesses and 5.8 million workers respectively — on Thursday called for the Prime Minister and EU negotiators to end"15 months of human poker."

The CBI and TUC said both parties should unequivocally guarantee the rights of 4 million European nationals who live in the UK.

The statement is noteworthy both for the strength of its language and for the fact that a business lobby group and a trade union have joined forces.

"A blight on the values of our nations"

Carolyn Fairbairn, director-general of the CBI, and Frances O'Grady, general secretary of the TUC, said in a statement: "After 15 months of human poker, the uncertainty facing 4 million European and UK citizens has become intolerable."

"It is a blight on the values of our nations. Millions of workers and thousands of firms are today united in their call to leaders on both sides to find an urgent solution. A clear guarantee of the right to remain for citizens in both the UK and EU 27 is needed within weeks.

"EU citizens account for 10% of registered doctors and 4% of registered nurses across the UK. Millions more work in the public and private sectors delivering public services and making a vital contribution to our economy.

"They need to hear that they will be allowed to remain in the UK, whatever the eventual outcome of negotiations. Not only is this important for our economy, it is the right thing to do."

The Institute of Directors (IOD), a group which represents 30,000 senior business leaders, also called on the government to guarantee the rights of EU citizens, and said on Thursday that both sides needed to display "further flexibility."

"We are pleased to see further developments on citizens' rights, but would warn both the UK and EU that further flexibility is needed in this and other areas to move the discussions on, at a faster pace. The clock is still ticking," said Allie Renison, head of EU and trade policy at the IoD.

Sticking point

The statement followed the end of the fourth round of UK-EU Brexit negotiations on Thursday, at which the UK and EU reportedly made "some progress" on the EU citizens issue.

Prime Minister Theresa May and senior cabinet colleagues have consistently refused to guarantee the right of EU nationals to remain in the UK after Brexit.

Trade minister Liam Fox has described EEA nationals in the UK as one of the government's "main bargaining chips" in upcoming negotiations, and May has argued that the UK would be left "high and dry" in negotiations by guaranteeing the rights of EEA nationals without receiving similar assurances for UK nationals living in the EU.

The major sticking point remains the post-Brexit role of the European Court of Justice. The EU's chief negotiator Michel Barnier insists it is "indispensable" in ensuring the "consistency" of the rights of EU citizens living in the UK. The UK intends to leave the ECJ, and the prime minister has described it as a "red line" in negotiations.